HORT/AGRO 689: Molecular & Biological Techniques in Plant Breeding

1. HORT/AGRO 689: Molecular & Biological Techniques in Plant Breeding Dr. Monica Menz Assistant Professor Institute for Plant Genomics & Biotechnology 458-1368 mmenz@tamu.edu Dr. Stephen R. King Associate Professor Department of Horticultural Sciences HFSB 409 and Centeq 120A 845-2937 or 229-8746 srking@tamu.edu

2. This Course is Not: • A molecular biology course • Students should have an understanding of basic molecular biological techniques used in plant improvement • Techniques will be covered, but focus will be on Applications of the technology, not Development • A genetics course • Students should have an understanding of the principles of genes (including structure & function) and heritability

3. This Course Is: • A review of special tools and techniques that can be applied to a plant breeding program with a focus on the role of genetics • An introduction to the applications of new technologies, including molecular biology, from a plant breeding perspective • (Hopefully) An interactive investigation of special considerations to the application of these new technologies

4. Required Reading • J. Knight. 2003. A dying breed. Nature. 421:568-570

5. Important Events in Plant Improvement • 1865: Gregor Mendel lectures & then publishes “Experiments with Plant Hybrids” (in 1866) where he describes how traits are inherited and the Laws of Inheritance: 1) Segregation 2) Independent Assortment • 1869: DNA Identified in white blood cells • 1900: Rediscovery of Mendel’s work: • Tschermark: Did not understand the concepts of Dominance, Phenotypic ratios or observation & theory • deVries: Inferred Mendel’s 1st Law, but did not separate gene transmission & expression • Correns: Clearly understood Mendel’s data; Dominance = analagen; segregation is a pair of factors; understood 9:3:3:1 ratio’s; but he did confuse segregation within a trait to segregation between traits

6. Important Events in Plant Improvement • 1904: Gene Linkage demonstrated • 1905 – 1908: Modifier genes described • 1909: Relationship between genes & proteins • 1913: First genetic map constructed • 1920’s: Hybrid cultivars adopted • 1926: Pioneer Hi-Bred formed • 1928: Transformation observed in bacteria • 1935: Pure DNA isolated • 1941: One gene – One enzyme hypothesis • 1953: Molecular structure of DNA discovered

7. Important Events in Plant Improvement • 1953: Plasmids observed to transfer genetic markers between bacteria • 1959: Gene regulation established in the DNA sequence • 1966: Genetic code deciphered • 1969: First gene isolated • 1972: First recombinant DNA created • 1972: First successful DNA cloning performed • 1973: First recombinant DNA organism created • 1978: RFLPs are discovered • 1980: PCR technique invented • 1984: DNA fingerprinting developed

8. Discoveries Usually Take Time to Reach Potential • 1838: Theory of totipotency developed • 1939: Carrot callus cultures cultivated • 1959: Plants regenerated from carrot cultures • 1946: Source of dwarfing gene sent to US • 1962: Dwarfing gene used to start the Green Revolution • 1943: Mexican Agricultural Program initiated • 1957: Mexico became self-sufficient in wheat production • 1951: Barbara McClintock reported her work on transposable elements in maize • 1983: Barbara McClintock received Nobel Prize for work on transposable elements

9. History of Modern Plant Breeding • Mendelian Genetics – early 1900s • Resulted in Hybrid Cultivars • Chemical Agriculture – 1940s • Allowed more freedom for breeders to select high yielding, high quality genotypes • Green Revolution – 1960s • Combined Modern Varieties with Chemical Fertilizers

10. World’s Food Supply vs. Increasing Population Green Revolution Chemical Agriculture Mendel

11. Modern Agriculture has not been readily accepted • LUTHER BURBANK "We have recently advanced our knowledge of genetics to the point where we can manipulate life in a way never intended by nature." "We must proceed with the utmost caution in the application of this new found knowledge.“ • 1906

12. Resistance to the Green Revolution • India resisted the importing of “exotic” wheat in 1965: • These varieties would “destroy Indian agriculture” warned scientists. • The Minister of Agriculture allowed for the use of the new varieties because of the crisis facing Indian agriculture: • Predictions gave the country two years before wide-spread famine engulfed the country. • Within two years, a bumper crop helped feed the nation (http://www.observerindia.com/news/200011/24/commentary03.htm)

13. Resistance to Chemical Agriculture • No References to resistance prior to wide-spread use (acceptance) • Indiscriminate use of Chemical Agriculture probably poses the greatest risk to public health of all modern farming practices

14. World’s Food Supply vs. Increasing Population ? Green Revolution Chemical Agriculture Mendel

15. Where will the next major advance in Agricultural Production come from? • Plant Breeders will likely play a major role: • 2 of the 3 major advances in the 20th Century were directly attributable to plant breeding • Modern Biotechnology is poised to provide a major advance: • But only if this basic science is understood and used by the applied sciences • Plant Breeders are the logical avenue for the application of biotechnology

16. Uses of Cell & Molecular Biology in a Breeding Program • Source of Genetic Variation • The Ultimate Driving Force Behind All New Technologies • To Speed Variety Development • Faster Source for Genetic Variation • Faster, more Efficient Assimilation of Traits • High Through-put Screening • To Improve Quality • Purity/Hybridity Testing

17. Modern Plant Breeding Tools • Tissue Culture Applications • Micropropagation • Germplasm preservation • Somaclonal variation & mutation selection • Embryo Culture • Haploid & Dihaploid Production • In vitro hybridization – Protoplast Fusion • Industrial Products from Cell Cultures

18. Reading Assignment: D.C.W. Brown, T.A. Thorpe. 1995. Crop improvement through tissue culture. World Journal of Microbiology and Biotechnology. 11(4):409-415 D.R. Miller, R.M. Waskom, M.A. Brick & P.L. Chapman. 1991. Transferring in vitro technology to the field. Bio/Technology. 9:143-146